In vehicle body shell construction, when joining the roof part to corresponding connection parts, thermal joining methods are generally used, such as, for example, resistance spot welding, laser welding or laser soldering.
During joining by resistance spot welding, a design may result in multi-sheet layers that are no longer weldable. In particular, the multi-sheet connection of thin sheets to thicker reinforcements constitutes a difficulty for resistance spot welding. Nevertheless, to be able to carry out the joining, one or more sheets have to be notched, as a result of which the vehicle structure is locally weakened.
In addition, a high level of investment is required for alternatives of laser welding or laser soldering.
Also, when using thermal joining methods, it is not readily possible to combine different materials, such as, for example, aluminum with steel or the connection to suitable plastics, for example CFRP materials.
According to the known prior art (U.S. Pat. No. 3,239,269), it is already being attempted to provide seamed connections at a number of points between the roof part and the adjacent components, but the main connections still always have to be produced by means of thermal joining methods.